1. Field of the Invention
This invention relates to lasers, and more particularly it relates to waveguide gas lasers excited with a transverse rf discharge.
2. Description of the Prior Art
A recent advance in the waveguide gas laser art involves pumping the laser by means of a transverse discharge at rf frequencies generally in the vhf-uhf range. Lasers of this type are disclosed in U.S. Pat. No. 4,169,251, issued Sept. 25, 1979 to K. D. Laakmann and assigned to the assignee of the present invention.
It is often desirable to increase the power output of a laser by increasing the length of the laser, and for ac pumped lasers, it is sometimes advantageous to increase the excitation frequency. Since the electrical length of a laser is proportional to the product of the excitation frequency and the physical length of the laser, increasing either the physical length or the excitation frequency, or both, results in a laser of longer electrical length. In the case of a transverse rf discharge-excited waveguide laser, if the electrical length is increased sufficiently, transmission line effects occur which degrade the discharge uniformity, thereby reducing operating efficiency and the obtainable output power.